Developing consensus on core outcome domains for assessing effectiveness in perioperative pain management: results of the PROMPT/IMI-PainCare Delphi Meeting

A core outcome set of measurement instruments for assessing effectiveness and efficacy of perioperative pain management: results of the international IMI-PainCare PROMPT Delphi consensus process

BACKGROUND

Effective perioperative pain management is crucial to prevent patient suffering, delayed recovery, chronic postsurgical pain, and long-term opioid use. However, the heterogeneous use of outcomes in studies complicates evidence synthesis and might not accurately reflect the experiences of individual patients. We initiated a consensus process to establish a core outcome set (COS) of patient-reported outcome measures (PROMs) in postoperative pain, building upon the earlier consensus on a COS of domains.

METHODS

Potential PROMs were identified via systematic literature searches for the domains pain intensity (with subdomains at rest and during activity), physical function, self-efficacy, and adverse events, followed by appraisal of psychometric properties according to the COnsensus-based Standards for the selection of health Measurement INstruments methodology. Then, a consensus meeting was convened, followed by a Delphi process with an international, multiprofessional panel of stakeholders, including those with lived experience. A conclusive consensus meeting approved the final COS of PROMs.

RESULTS

The final COS consists of one unidimensional numerical rating scale for assessing pain intensity on average, worst pain intensity, pain intensity at rest, and procedure-specific pain intensity during activity; one unidimensional scale for pain interfering with activities in bed; one procedure-specific scale for assessing physical function; the IMI-PainCare PROMPT adaptation of the Arthritis Self-Efficacy Scale for assessing self-efficacy; and the IMI-PainCare PROMPT adaptation of the Opioid-Related Symptom Distress Scale for assessing adverse events.

CONCLUSIONS

Comprehensive use of a core outcome set will help harmonise outcome assessment, facilitate comparisons between studies, promote patient-centred research, and improve postoperative pain care.

A critical approach to research on perioperative pain management

Optimal postoperative pain management is a prerequisite for enhancing functional recovery after surgery. However, many studies assessing analgesic interventions have limitations. Consequently, further improvements in study design are urgently needed. In this focused editorial, we critically review prevalent trial designs and outcome measures including treatment-related adverse events evaluating analgesic interventions. Novel clinical trial designs should improve efficiency and enhance the likelihood of detecting relevant treatment effects. Cohort and database studies using propensity score matching and directed acyclic graphs could provide real-world generalisable information. Procedure-specific and patient-specific trials should allow identification of subpopulations most likely to benefit from a particular intervention after a specific surgical procedure and thus ascertain optimal analgesic strategies in challenging populations.

Development of a Core Outcome Set of Domains to Evaluate Acute Pain Treatment After Lumbar Spine Surgery: A Modified Delphi Study

BACKGROUND

After lumbar spine surgery, a Core Outcome Set (COS) for acute pain is essential to ensure that the most meaningful outcomes are monitored consistently in the perioperative period. The aim of the present study was to consent on a COS for assessing the efficacy of acute pain management for patients undergoing lumbar spinal surgery.

METHOD

A modified Delphi procedure was conducted among a national (Dutch) expert panel. External endorsement of the final COS was conducted among an international panel of anaesthesiologists and the Dutch chronic pain patient association.

RESULTS

A panel of 35 experts representing 10 stakeholder groups, including orthopaedic surgeons, anaesthesiologists, patient representatives, physician assistants, researchers, a neurosurgeon, nurses, and a psychologist, took part in the Delphi procedure. Five outcome domains reached consensus for inclusion in this COS. This COS contains the following domains: pain intensity, analgesic use, early mobilisation, length of stay, and adverse events. Of an international panel of 27 key opinion leaders, 77% agreed on the final COS. The patient association also consented to the final COS.

CONCLUSIONS

A COS to evaluate acute pain treatment after lumbar surgery is proposed after national Delphi consensus rounds and (international) external endorsement. Future research should focus on determining suitable measurement instruments, assessing feasibility, validation, and implementation of the COS in daily clinical practice and research.

SIGNIFICANCE

This research proposes a clinically relevant spine-specific core outcome set (COS) of domains focusing on the acute postoperative phase (until 30 days). This is the first COS for evaluation of acute pain after lumbar spine surgery.

Blood proteomics and multimodal risk profiling of human volunteers after incision injury: A translational study for advancing personalized pain management after surgery

A significant number of patients develop chronic pain after surgery, but prediction of those who are at risk is currently not possible. Thus, prognostic prediction models that include bio-psycho-social and physiological factors in line with the complex nature of chronic pain would be urgently required. Here, we performed a translational study in male volunteers before and after an experimental incision injury. We determined multi-modal features ranging from pain characteristics and psychological questionnaires to blood plasma proteomics. Outcome measures included pain intensity ratings and the extent of the area of hyperalgesia to mechanical stimuli surrounding the incision, as a proxy of central sensitization. A multi-step logistic regression analysis was performed to predict outcome measures based on feature combinations using data-driven cross-validation and prognostic model development. Phenotype-based stratification resulted in the identification of low and high responders for both outcome measures. Regression analysis revealed prognostic proteomic, specific psychophysical, and psychological features. A combinatorial set of distinct features enabled us to predict outcome measures with increased accuracy compared to using single features. Remarkably, in high responders, protein network analysis suggested a protein signature characteristic of low-grade inflammation. Alongside, in silico drug repurposing highlighted potential treatment options employing antidiabetic and anti-inflammatory drugs. Taken together, we present here an integrated pipeline that harnesses bio-psycho-physiological data for prognostic prediction in a translational approach. This pipeline opens new avenues for clinical application with the goal of stratifying patients and identifying potential new targets, as well as mechanistic correlates, for postsurgical pain.

Anterior quadratus lumborum blocks for postoperative pain treatment following intra-abdominal surgery: A systematic review with meta-analyses and trial sequential analyses

BACKGROUND

The anterior quadratus lumborum (QL) block may be used for postoperative pain management for intra-abdominal surgeries, but the evidence is uncertain. We aimed to investigate the benefit and harm of the anterior QL block compared to placebo/no block for intra-abdominal surgery.

METHODS

We searched Medline, Embase, and CENTRAL for randomized controlled trials investigating anterior QL block for postoperative pain management for adult patients undergoing any intra-abdominal surgery. The two co-primary outcomes were cumulative 24-h opioid consumption and serious adverse events. We performed meta-analysis, trial sequential analysis (TSA), assessed the risk of bias, and present the certainty of evidence with the Grading of Recommendations, Assessment, Development and Evaluation approach.

RESULTS

Thirty-five trials randomizing 2418 patients were included in the meta-analyses. Anterior QL block may reduce cumulative 24-h intravenous opioid consumption compared to placebo/no block (MD -10.42 mg, 96.7% CI -14.83 to -6.01, TSA-adjusted CI -17.03 to -3.82, p < .01). Two trials reported on SAEs. Anterior QL block may have little to no effect on the number of serious adverse events compared to placebo (RR 1.49, 96.7% CI 0.19 to 11.47, p = .68), but the evidence is very uncertain. All trial results were assessed as being high risk of bias.

CONCLUSIONS

The anterior QL block may reduce cumulative 24-h opioid consumption. Reported serious adverse events were few and the anterior QL block may have little to no effect on the number of SAEs, but the evidence was very uncertain.

Development of a core outcome set of quality indicators for enhanced recovery after surgery in minimally invasive cardiac heart valve surgery by interprofessional Delphi consensus

OBJECTIVES

A core outcome set (COS) giving indicators of the quality of the process for minimally invasive valve surgery embedded into enhanced recovery after surgery (ERAS) protocols should be developed.

METHODS

Using web-based questionnaires, a Delphi process with three rounds was conducted from January to December 2022. Prior to the rounds, a systematic database search was performed identifying potential quality parameters. Experts for the panel were selected reflecting the interprofessional nature of the ERAS protocol. In the first round, participants could make suggestions of indicators in the pre-, intra- or postoperative and rehabilitative phase. These suggestions form together with the indicators of the literature a first indicator list. In the second round, participants could rate the relevance of the indicators resulting in a condensed indicator list. The third round was performed for further condensation based on importance ranking of the remaining indicators.

RESULTS

Three studies could be included in the systematic literature search providing a list of 22 indicators. Twenty-one experts participated in the Delphi survey. The experts named 315 indicators in the first round. After condensation in two further rounds, the final COS consisted of 24 indicators in the categories structure, process, outcome and complications.

CONCLUSIONS

A consensual minimum set of quality measurements during pre-, intra- and postoperative and rehabilitation phase for patients with minimally invasive heart surgery is now available for enhancing the quality of clinical practice and facilitating comparisons across different ERAS programs.

Present and Future of Pharmacological Management for Acute Moderate-to-Severe Postoperative, Traumatic, or Musculoskeletal Pain in Europe: A Narrative Review

Acute moderate-to-severe pain is common after surgery, trauma, or musculoskeletal injury, but its management remains suboptimal. Current single-agent treatments are limited by safety concerns, narrow therapeutic windows, and abuse potential, leaving substantial unmet needs. Here, we aimed to review guidelines for the management of acute moderate-to-severe post-surgical, trauma-related, or musculoskeletal pain in adults and discuss existing and potential future analgesics in this setting. We searched PubMed to identify relevant guidelines and existing analgesics for acute pain. To identify compounds in development, we searched ClinicalTrials.gov and the European Union Clinical Trials Register. Guidelines universally recognize the limitations of single-agent analgesics (particularly those with a single mechanism of action [MoA]) and recommend a multimodal approach as an established standard for acute pain. The benefit-risk profiles of traditional treatments, including paracetamol (acetaminophen), nonsteroidal anti-inflammatory drugs, selective cyclooxygenase-2 inhibitors, and opioids, can be improved by combining agents targeting different pain pathways. In multimodal approaches, lower doses of constituent agents can be used to achieve the same or superior analgesic effects relative to the individual agents. In some cases, novel formulations and co-crystal technology offer enhanced physicochemical and pharmacokinetic properties over individual agents. Lastly, initiatives to increase patient awareness and education around pain management may improve treatment satisfaction and quality of life, and hasten recovery. In conclusion, management of acute moderate-to-severe pain remains inadequate. Multimodal analgesics may offer advantages over traditional single-agent treatments (that often have a single MoA) for acute moderate-to-severe post-surgical, trauma-related, or musculoskeletal pain in adults. Multimodal analgesics, combined with patient education initiatives and non-pharmacological measures, when necessary, offer promise in addressing unmet needs in this setting.

Prolonged magnesium sulfate infusion as adjuvant analgesia in postoperative transplant patients in the pediatric ICU: Preliminary results of a feasibility study

The opioid crisis has emphasized identification of opioid-sparing analgesics. This study was designed as a prospective trial with retrospective control group to determine feasibility for implementing a high-dose prolonged magnesium sulfate infusion for adjuvant analgesia in the pediatric intensive care unit. Approval was granted for study of children receiving total pancreatectomy with islet cell autotransplantation and liver transplantation ages 3-18 years. Study exclusions were pregnancy, neuromuscular disease, hypersensitivity, preoperative creatinine >1.5 times upper limit normal, arrhythmia or pacemaker presence, and clinician concern. Eleven patients were enrolled between January 2020 and December 2022. Magnesium sulfate bolus (50 mg/kg) followed by intravenous infusion (15 mg/kg/h) was initiated in the operating room and extended postoperatively (maximum 48 h). Serum magnesium levels were monitored serially. To prioritize safety, infusion dose was decreased by 5 mg/kg/h for levels greater than 3.5 mg/dL. Clinical team otherwise followed standard multimodal pain practice. Primary outcome was oral morphine equivalent per kg per day during intensive care course (maximum 7 days). Secondary outcomes focused primarily on magnesium safety, including hemodynamic variables, electrolyte variables, respiratory support, and opioid-related side effects. There were no serious adverse events. Treatment group trended toward slightly higher intravenous fluid requirement (~1 bolus), however no increase in blood product. Treatment and control groups were otherwise comparable in targeted outcomes and overall adverse event profile. Use of a high-dose magnesium sulfate infusion protocol for analgesic postoperative use in select transplant recipients appears feasible for continued optimization of study in the PICU.

Capabilities Toward Intravenous Patient-Controlled Analgesia: A Cross-Sectional Study of Registered Nurses Working in Two Tertiary Hospitals in China and Thailand

BACKGROUND

An increased interest has been observed in the wide use of intravenous patient-controlled analgesia (IV-PCA) to control acute postoperative pain in both China and Thailand. The safety and efficacy of IV-PCA in patient care requires competent and capable staff nurses. This study aimed to appraise the capabilities of Thai and Chinese registered nurses regarding IV-PCA as a guide to develop educational programs.

METHOD

A descriptive cross-sectional survey was conducted with 203 Chinese and 270 Thai registered nurses. An anonymous self-report questionnaire addressing 6 domains of capabilities toward IV-PCA was used to collect the data. Descriptive and inferential statistics were employed to analyze the data.

RESULTS

The study found that the mean percentage scores (MPS) of the overall capability on IV-PCA of the Thai and Chinese nurse participants were 55.5 (mean [M] = 57.3, standard deviation [SD] = 4.9) and 62.6 (M = 58.7, SD = 13.0), respectively, which indicated very low and low levels. Barriers to the use and care of patients receiving IV-PCA after surgery according to the Thai and Chinese nurse participants included a lack of knowledge and systematic training regarding IV-PCA and a lack of first-hand experience in providing care for IV-PCA patients.

CONCLUSION

The study results call for intensive and effective training and education concerning all domains for registered nurses involved with patients receiving IV-PCA.

Measurement of acute postoperative pain intensity in orthopedic trials: a qualitative concept elicitation study

BACKGROUND AND PURPOSE

Pain intensity is an important outcome in clinical trials of surgery because pain relief is important to patients. Currently, recommended scales are the numeric rating scale 0-10 and visual analogue scale. However, these scales allow for considerable influence of individual imagination, previous experience, and coping skills, limiting proficiency in comparative clinical trials. We aimed to explore postoperative expressions of "how much it hurts"-the first step to improve pain intensity measurement.

METHODS

This was a qualitative study using inductive content analysis: words and visual cues describing pain intensity were collected from (i) existing pain intensity measures by search of COSMIN, PubMed, and Google, (ii) patient interviews recorded and transcribed word-for-word, (iii) clinician interviews transcribed likewise, and (iv) 100 patient telephone interviews with notes taken. After familiarization, the collected expressions were labelled inductively in categories and assembled in tables (case and theme-based matrices).

RESULTS

Descriptors fell into 12 categories: intensity (slight/strong), evaluative (negligible/unbearable), cognitive impact (distracting/can be ignored), activity impact (limits some/all activity), sleep impact (can/cannot sleep), examples (like stubbing a toe), physical signs (crying/writhing), associated symptoms (nauseating/tiring), treatment (ice helps/need morphine), affective (annoying/dreadful), discriminative (aching/piercing), and general recovery (hindering recovery/functional interference). Many visual cues were also identified. Literature and recorded interviews gave rise to the categories, and telephone interviews found saturation, providing no further categories.

CONCLUSION

Pain intensity is expressed by terms that fall into 12 categories and by a variety of graphic elements. This advances development of a patient-reported outcome measure of pain intensity for orthopedic trials.

Peri-operative pain management in adults: a multidisciplinary consensus statement from the Association of Anaesthetists and the British Pain Society

BACKGROUND

Nearly half of adult patients undergoing surgery experience moderate or severe postoperative pain. Inadequate pain management hampers postoperative recovery and function and may be associated with adverse outcomes. This multidisciplinary consensus statement provides principles that might aid postoperative recovery, and which should be applied throughout the entire peri-operative pathway by healthcare professionals, institutions and patients.

METHODS

We conducted a directed literature review followed by a four-round modified Delphi process to formulate recommendations for organisations and individuals.

RESULTS

We make recommendations for the entire peri-operative period, covering pre-admission; admission; intra-operative; post-anaesthetic care unit; ward; intensive care unit; preparation for discharge; and post-discharge phases of care. We also provide generic principles of peri-operative pain management that clinicians should consider throughout the peri-operative pathway, including: assessing pain to facilitate function; use of multimodal analgesia, including regional anaesthesia; non-pharmacological strategies; safe use of opioids; and use of protocols and training for staff in caring for patients with postoperative pain.

CONCLUSIONS

We hope that with attention to these principles and their implementation, outcomes for adult patients having surgery might be improved.

[What determines the overall quality of postoperative pain management? A question of perspective]

BACKGROUND

The outcome domains pain intensity, pain-related interference, side effects, (treatment) information, participation and personal interaction have all been identified as relevant factors in the management of perioperative pain. However, it is not yet clear which of these are particularly significant for the subjectively perceived overall quality of postoperative pain management.

AIM

A newly developed questionnaire was used in this cross-sectional study to assess the relevance of these domains for patients and compare the relevance to healthcare professionals (HCP).

METHODS

The patient survey (n = 40) was conducted on the first postoperative day at Jena University Hospital, Germany. In order to investigate group differences, 63 HCP (disciplines: n = 15 anaesthesiology, n = 17 surgery, n = 31 nursing) were recruited. The questionnaire primarily included all pairwise comparisons between the domains with regard to the overall quality of postoperative pain management. The resulting sum scores for each domain were the primary outcome measure, which were analysed using generalized estimating equations.

RESULTS

Within the group of patients, there were significant differences in the prioritization of the six outcome domains, with personal interaction followed by intensity and interference having received the highest ratings. There were also significant differences within the domains between the perspectives of patients and HCP, as well as between the HCP themselves.

CONCLUSIONS

The study demonstrates that personal interaction and the reduction of pain intensity and interference are three key factors that are significant for patients' experience of postoperative pain management. However, the extent to which the harmonisation of these three factors with those given prominence by HCP would positively impact postoperative pain management remains unclear and should be investigated further.

Systematic reviews and quality assessment of patient-reported outcome measures for physical function in comparative effectiveness studies regarding acute postoperative pain after total knee arthroplasty-Do we need to start all over again?

BACKGROUND AND OBJECTIVE

Recently, a consensus process specified a core outcome set (COS) of domains to be assessed in each comparative effectiveness research and clinical practice related to acute postoperative pain. Physical function (PF) was one of these domains. The aim of this review was to investigate which patient-reported outcome measures (PROMs) are used to assess PF after total knee arthroplasty (TKA) in clinical trials and if they fulfil basic requirements for a COS of PROMs based on their psychometric properties.

METHODS

A systematic review of randomized controlled trials and observational studies based on a search in MEDLINE, EMBASE and CENTRAL was undertaken. PROMs and performance measures were extracted and investigated, including evaluation of psychometric properties of PROMs based on COSMIN recommendations.

RESULTS

From initially 2896 identified records, 479 studies were included in the qualitative synthesis. Only 87 of these trials (18%) assessed PF using PROMs, whereas especially performance outcome measures were used in 470 studies (98%). Application of the 'COSMIN Risk-of-Bias-Box 1' to 13 of the 14 identified PROMs resulted in insufficient content validity of the included PROMs regarding the target population based on the inauguration or development articles.

CONCLUSION

Our data indicate that a patient-centred postoperative assessment of PF in pain-related clinical trials early after TKA is not common, even though patient-reported assessment is widely recommended. In addition, none of the applied PROMs shows content validity based on their inauguration or development articles for the assessment of postoperative pain-related PF after TKA.

SIGNIFICANCE

A systematic search for patient-reported outcome measures assessing postoperative, pain-related physical function after total knee arthroplasty in clinical trials and assessment of their content validity revealed none that fulfilled requirements based on COSMIN recommendations.

Effectiveness of dexmedetomidine on patient-centred outcomes in surgical patients: a systematic review and Bayesian meta-analysis

BACKGROUND

Dexmedetomidine is increasingly used for surgical patients requiring general anaesthesia. However, its effectiveness on patient-centred outcomes remains uncertain. Our main objective was to evaluate the patient-centred effectiveness of intraoperative dexmedetomidine for adult patients requiring surgery under general anaesthesia.

METHODS

We conducted a systematic search of MEDLINE, Embase, CENTRAL, Web of Science, and CINAHL from inception to October 2023. Randomised controlled trials (RCTs) comparing intraoperative use of dexmedetomidine with placebo, opioid, or usual care in adult patients requiring surgery under general anaesthesia were included. Study selection, data extraction, and risk of bias assessment were performed by two reviewers independently. We synthesised data using a random-effects Bayesian regression framework to derive effect estimates and the probability of a clinically important effect. For continuous outcomes, we pooled instruments with similar constructs using standardised mean differences (SMDs) and converted SMDs and credible intervals (CrIs) to their original scale when appropriate. We assessed the certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Our primary outcome was quality of recovery after surgery. To guide interpretation on the original scale, the Quality of Recovery-15 (QoR-15) instrument was used (range 0-150 points, minimally important difference [MID] of 6 points).

RESULTS

We identified 49,069 citations, from which 44 RCTs involving 5904 participants were eligible. Intraoperative dexmedetomidine administration was associated with improvement in postoperative QoR-15 (mean difference 9, 95% CrI 4-14, n=21 RCTs, moderate certainty of evidence). We found 99% probability of any benefit and 88% probability of achieving the MID. There was a reduction in chronic pain incidence (odds ratio [OR] 0.42, 95% CrI 0.19-0.79, n=7 RCTs, low certainty of evidence). There was also increased risk of clinically significant hypotension (OR 1.98, 95% CrI 0.84-3.92, posterior probability of harm 94%, n=8 RCTs) and clinically significant bradycardia (OR 1.74, 95% CrI 0.93-3.34, posterior probability of harm 95%, n=10 RCTs), with very low certainty of evidence for both. There was limited evidence to inform other secondary patient-centred outcomes.

CONCLUSIONS

Compared with placebo or standard of care, intraoperative dexmedetomidine likely results in meaningful improvement in the quality of recovery and chronic pain after surgery. However, it might increase clinically important bradycardia and hypotension.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023439896).

Perioperative pain management with regional analgesia techniques for visceral cancer surgery: A systematic review and meta-analysis

STUDY OBJECTIVE

Regional analgesia following visceral cancer surgery might provide an advantage but evidence for best treatment options related to risk-benefit is unclear.

DESIGN

Systematic review of randomized controlled trials (RCT) with meta-analysis and GRADE assessment.

SETTING

Postoperative pain treatment.

PATIENTS

Adult patients undergoing visceral cancer surgery.

INTERVENTIONS

Any kind of peripheral (PRA) or epidural analgesia (EA) with/without systemic analgesia (SA) was compared to SA with or without placebo treatment or any other regional anaesthetic techniques.

MEASUREMENTS

Primary outcome measures were postoperative acute pain intensity at rest and during activity 24 h after surgery, the number of patients with block-related adverse events and postoperative paralytic ileus.

MAIN RESULTS

59 RCTs (4345 participants) were included. EA may reduce pain intensity at rest (mean difference (MD) -1.05; 95% confidence interval (CI): -1.35 to -0.75, low certainty evidence) and during activity 24 h after surgery (MD -1.83; 95% CI: -2.34 to -1.33, very low certainty evidence). PRA likely results in little difference in pain intensity at rest (MD -0.75; 95% CI: -1.20 to -0.31, moderate certainty evidence) and pain during activity (MD -0.93; 95% CI: -1.34 to -0.53, moderate certainty evidence) 24 h after surgery compared to SA. There may be no difference in block-related adverse events (very low certainty evidence) and development of paralytic ileus (very low certainty of evidence) between EA, respectively PRA and SA.

CONCLUSIONS

Following visceral cancer surgery EA may reduce pain intensity. In contrast, PRA had only limited effects on pain intensity at rest and during activity. However, we are uncertain regarding the effect of both techniques on block-related adverse events and paralytic ileus. Further research is required focusing on regional analgesia techniques especially following laparoscopic visceral cancer surgery.

Chronic postsurgical pain: A European survey

BACKGROUND

Chronic postsurgical pain (CPSP) is a clinical problem, and large prospective studies are needed to determine its incidence, characteristics, and risk factors.

OBJECTIVE

To find predictive factors for CPSP in an international survey.

DESIGN

Observational study.

SETTING

Multicentre European prospective observational trial.

PATIENTS

Patients undergoing breast cancer surgery, sternotomy, endometriosis surgery, or total knee arthroplasty (TKA).

METHOD

Standardised questionnaires were completed by the patients at 1, 3, and 7 days, and at 1, 3, and 6 months after surgery, with follow-up via E-mail, telephone, or interview.

MAIN OUTCOME MEASURE

The primary goal of NIT-1 was to propose a scoring system to predict those patient likely to have CPSP at 6 months after surgery.

RESULTS

A total of 3297 patients were included from 18 hospitals across Europe and 2494 patients were followed-up for 6 months. The mean incidence of CPSP at 6 months was 10.5%, with variations depending on the type of surgery: sternotomy 6.9%, breast surgery 7.4%, TKA 12.9%, endometriosis 16.2%. At 6 months, neuropathic characteristics were frequent for all types of surgery: sternotomy 33.3%, breast surgery 67.6%, TKA 42.4%, endometriosis 41.4%. One-third of patients experienced CPSP at both 3 and 6 months. Pre-operative pain was frequent for TKA (leg pain) and endometriosis (abdomen) and its frequency and intensity were reduced after surgery. Severe CPSP and a neuropathic pain component decreased psychological and functional wellbeing as well as quality of life. No overarching CPSP risk factors were identified.

CONCLUSION

Unfortunately, our findings do not offer a new CPSP predictive score. However, we present reliable new data on the incidence, characteristics, and consequences of CPSP from a large European survey. Interesting new data on the time course of CPSP, its neuropathic pain component, and CPSP after endometriosis surgery generate new hypotheses but need to be confirmed by further research.

TRIAL REGISTRATION

clinicaltrials.gov ID: NCT03834922.

Regional anaesthesia for postoperative pain management following laparoscopic, visceral, non-oncological surgery a systematic review and meta-analysis

BACKGROUND

Postoperative pain management following laparoscopic, non-oncological visceral surgery in adults is challenging. Regional anaesthesia could be a promising component in multimodal pain management.

METHODS

We performed a systematic review and meta-analysis with GRADE assessment. Primary outcomes were postoperative acute pain intensity at rest/during movement after 24 h, the number of patients with block-related adverse events and the number of patients with postoperative paralytic ileus.

RESULTS

82 trials were included. Peripheral regional anaesthesia combined with general anaesthesia versus general anaesthesia may result in a slight reduction of pain intensity at rest at 24 h (mean difference (MD) - 0.72 points; 95% confidence interval (CI) - 0.91 to - 0.54; I2 = 97%; low-certainty evidence), which was not clinically relevant. The evidence is very uncertain regarding the effect on pain intensity during activity at 24 h (MD -0.8 points; 95%CI - 1.17 to - 0.42; I2 = 99%; very low-certainty evidence) and on the incidence of block-related adverse events. In contrast, neuraxial regional analgesia combined with general anaesthesia (versus general anaesthesia) may reduce postoperative pain intensity at rest in a clinical relevant matter (MD - 1.19 points; 95%CI - 1.99 to - 0.39; I2 = 97%; low-certainty evidence), but the effect is uncertain during activity (MD - 1.13 points; 95%CI - 2.31 to 0.06; I2 = 95%; very low-certainty evidence). There is uncertain evidence, that neuraxial regional analgesia combined with general anaesthesia (versus general anaesthesia) increases the risk for block-related adverse events (relative risk (RR) 5.11; 95%CI 1.13 to 23.03; I2 = 0%; very low-certainty evidence).

CONCLUSION

This meta-analysis confirms that regional anaesthesia might be an important part of multimodal postoperative analgesia in laparoscopic visceral surgery, e.g. in patients at risk for severe postoperative pain, and with large differences between surgical procedures and settings. Further research is required to evaluate the use of adjuvants and the additional benefit of regional anaesthesia in ERAS programmes.

PROTOCOL REGISTRATION

PROSPERO CRD42021258281.

Co-crystal of Tramadol-Celecoxib Versus Tramadol or Placebo for Acute Moderate-to-Severe Pain After Oral Surgery: Randomized, Double-Blind, Phase 3 Trial (STARDOM1)

INTRODUCTION

Co-crystal of tramadol-celecoxib (CTC) is the first analgesic co-crystal for acute pain. This completed phase 3 multicenter, double-blind trial assessed the efficacy and safety/tolerability of CTC in comparison with that of tramadol in the setting of moderate-to-severe pain up to 72 h after elective third molar extraction requiring bone removal.

METHODS

Adults (n = 726) were assigned randomly to five groups (2:2:2:2:1): orally administered twice-daily CTC 100 mg (44 mg rac-tramadol hydrochloride/56 mg celecoxib; n = 164), 150 mg (66/84 mg; n = 160) or 200 mg (88/112 mg; n = 160); tramadol 100 mg four times daily (n = 159); or placebo four times daily (n = 83). Participants in CTC groups also received twice-daily placebo. The full analysis set included all participants who underwent randomization. The primary endpoint was the sum of pain intensity differences over 0 to 4 h (SPID0-4; visual analog scale). Key secondary endpoints included 4-h 50% responder and rescue medication use rates. Safety endpoints included adverse events (AEs), laboratory measures, and Opioid-Related Symptom Distress Scale (OR-SDS) score.

RESULTS

All CTC doses were superior to placebo (P < 0.001) for primary and key secondary endpoints. All were superior to tramadol for SPID0-4 (analysis of covariance least squares mean differences [95% confidence interval]: - 37.1 [- 56.5, - 17.6], - 40.2 [- 59.7, - 20.6], and - 41.7 [- 61.2, - 22.2] for 100, 150, and 200 mg CTC, respectively; P < 0.001) and 4-h 50% responder rate. Four-hour 50% responder rates were 32.9% (CTC 100 mg), 33.8% (CTC 150 mg), 40.6% (CTC 200 mg), 20.1% (tramadol), and 7.2% (placebo). Rescue medication use was lower in the 100-mg (P = 0.013) and 200-mg (P = 0.003) CTC groups versus tramadol group. AE incidence and OR-SDS scores were highest for tramadol alone.

CONCLUSIONS

CTC demonstrated superior pain relief compared with tramadol or placebo, as well as an improved benefit/risk profile versus tramadol.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02982161; EudraCT number, 2016-000592-24.

Perioperative pain management models in four European countries: A narrative review of differences, similarities and future directions

There is general agreement that acute pain management is an important component of perioperative medicine. However, there is no consensus on the best model of care for perioperative pain management, mainly because evidence is missing in many aspects. Comparing the similarities and differences between countries might reveal some insights into different organisational models and how they work. Here, we performed a narrative review to describe and compare the structures, processes and outcomes of perioperative pain management in the healthcare systems of four European countries using Donabedian's framework as a guide. Our comparison revealed many similarities, differences and gaps. Different structures of acute pain services in the four countries with no common definition and standards of care were found. Protocols have been implemented in all countries and guidelines in some. If outcome is assessed, it is mainly pain intensity, and many patients experiencing more intense pain than others have common risk factors (e.g. preoperative pain, preoperative opioid intake, female sex and young age). Outcome assessment beyond pain intensity (such as pain-related physical function, which is important for early rehabilitation and recovery) is currently not well implemented. Developing common quality indicators, a European guideline for perioperative pain management (e.g. for patients at high risk for experiencing severe pain and other outcome parameters) and common criteria for acute pain services might pave the way forward for improving acute pain management in Europe. Finally, the education of general and specialist staff should be aligned in Europe, for example, by using the curricula of the European Pain Federation (EFIC).

Perioperative pain management for appendicectomy: A systematic review and Procedure-specific Postoperative Pain Management recommendations

BACKGROUND

Despite being a commonly performed surgical procedure, pain management for appendicectomy is often neglected because of insufficient evidence on the most effective treatment options.

OBJECTIVE

To provide evidence-based recommendations by assessing the available literature for optimal pain management after appendicectomy.

DESIGN AND DATA SOURCES

This systematic review-based guideline was conducted according to the PROSPECT methodology. Relevant randomised controlled trials, systematic reviews and meta-analyses in the English language from January 1999 to October 2022 were retrieved from MEDLINE, Embase and Cochrane Databases using PRISMA search protocols.

ELIGIBILITY CRITERIA

We included studies on adults and children. If articles reported combined data from different surgeries, they had to include specific information about appendicectomies. Studies needed to measure pain intensity using a visual analogue scale (VAS) or a numerical rating scale (NRS). Studies that did not report the precise appendicectomy technique were excluded.

RESULTS

Out of 1388 studies, 94 met the inclusion criteria. Based on evidence and consensus, the PROSPECT members agreed that basic analgesics [paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs)] should be administered perioperatively for open and laparoscopic appendicectomies. A laparoscopic approach is preferred because of lower pain scores. Additional recommendations for laparoscopic appendicectomies include a three-port laparoscopic approach and the instillation of intraperitoneal local anaesthetic. For open appendicectomy, a preoperative unilateral transverse abdominis plane (TAP) block is recommended. If not possible, preincisional infiltration with local anaesthetics is an alternative. Opioids should only be used as rescue analgesia. Limited evidence exists for TAP block in laparoscopic appendicectomy, analgesic adjuvants for TAP block, continuous wound infiltration after open appendicectomy and preoperative ketamine and dexamethasone. Recommendations apply to children and adults.

CONCLUSION

This review identified an optimal analgesic regimen for open and laparoscopic appendicectomy. Further randomised controlled trials should evaluate the use of regional analgesia and wound infiltrations with adequate baseline analgesia, especially during the recommended conventional three-port approach.

REGISTRATION

The protocol for this study was registered with the PROSPERO database (Registration No. CRD42023387994).

Co-crystal of tramadol-celecoxib (CTC) for acute moderate-to-severe pain

OBJECTIVE

This narrative review aims to provide a clinical perspective on the potential role of co-crystal of tramadol-celecoxib (CTC) in the management of acute moderate-to-severe pain by synthesizing the available preclinical and clinical data, with emphasis on phase 3 trials.

METHODS

A non-systematic literature review was performed using a targeted PubMed search for articles published between January 1, 2000, and May 2, 2023; all publication types were permitted, and selected articles were limited to those published in English. Search results were manually reviewed to identify references based on their preclinical and clinical relevance to CTC and management of acute moderate-to-severe pain.

RESULTS

The crystalline structure of CTC alters the physicochemical properties of tramadol and celecoxib, modifying their pharmacokinetics. If taken in a free combination, tramadol reduces absorption of celecoxib. Conversely, administration of CTC slows tramadol absorption and lowers its maximum plasma concentration, while increasing celecoxib plasma concentration through its enhanced release. In clinical studies across models of acute moderate-to-severe pain, CTC demonstrated an early onset of analgesia, with improved efficacy and lower rescue medication use, compared with either agent alone. CTC's safety profile was in line with that expected for the individual components; no additive effects were observed. CTC exhibited tramadol-sparing effects, with efficacy seen at lower daily/cumulative opioid doses vs. tramadol alone.

CONCLUSIONS

Results from phase 3 trials suggest that the modified physicochemical properties of tramadol and celecoxib in CTC translate into an improved clinical benefit-risk profile, including fewer opioid-related adverse effects due to lower overall opioid dosing.

Peripheral Regional Anesthetic Techniques in Cardiac Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of this systematic review was to investigate postoperative pain outcomes and adverse events after peripheral regional anesthesia (PRA) compared to no regional anesthesia (RA), placebo, or neuraxial anesthesia in children and adults undergoing cardiac surgery.

DESIGN

A systematic review and meta-analysis with an assessment of the risk of bias (Cochrane RoB 1) and certainty of evidence (Grading of Recommendations, Assessment, Development, and Evaluation).

SETTING

Randomized controlled trials (RCTs).

PARTICIPANTS

Adults and children undergoing heart surgery.

INTERVENTIONS

Any kind of PRA compared to no RA or placebo or neuraxial anesthesia.

MEASUREMENTS AND MAIN RESULTS

In total, 33 RCTs (2,044 patients) were included-24 of these had a high risk of bias, and 28 were performed in adults. Compared to no RA, PRA may reduce pain intensity at rest 24 hours after surgery (mean difference [MD] -0.81 points, 95% CI -1.51 to -0.10; I2 = 92%; very low certainty evidence). Peripheral regional anesthesia, compared to placebo, may reduce pain intensity at rest (MD -1.36 points, 95% CI -1.59 to -1.13; I2 = 54%; very low certainty evidence) and during movement (MD -1.00 points, 95% CI -1.34 to -0.67; I² = 72%; very low certainty evidence) 24 hours after surgery. No data after pediatric cardiac surgery could be meta-analyzed due to the low number of included trials.

CONCLUSIONS

Compared to no RA or placebo, PRA may reduce pain intensity at rest and during movement. However, these results should be interpreted cautiously because the certainty of evidence is only very low.

Responsiveness of multiple patient-reported outcome measures for acute postsurgical pain: primary results from the international multi-centre PROMPT NIT-1 study

BACKGROUND

Postsurgical outcome measures are crucial to define the efficacy of perioperative pain management; however, it is unclear which are most appropriate. We conducted a prospective study aiming to assess sensitivity-to-change of patient-reported outcome measures assessing the core outcome set of domains pain intensity (at rest/during activity), physical function, adverse events, and self-efficacy.

METHODS

Patient-reported outcome measures were assessed preoperatively, on day 1 (d1), d3, and d7 after four surgical procedures (total knee replacement, breast surgery, endometriosis-related surgery, and sternotomy). Primary outcomes were sensitivity-to-change of patient-reported outcome measures analysed by correlating their changes (d1-d3) with patients' global impression of change and patients' specific impression of change items as anchor criteria. Secondary outcomes included identification of baseline and patient characteristic variables explaining variance in change for each of the scales and descriptive analysis of various patient-reported outcome measures from different domains and after different surgeries.

RESULTS

Of 3322 patients included (18 hospitals, 10 countries), data from 2661 patients were analysed. All patient-reported outcome measures improved on average over time; the median calculated sensitivity-to-change for all patient-reported outcome measures (overall surgeries) was 0.22 (range: 0.07-0.31, scale: 0-10); all changes were independent of baseline data or patient characteristics and similar between different procedures.

CONCLUSIONS

Pain-related patient-reported outcome measures have low to moderate sensitivity-to-change; those showing higher sensitivity-to-change from the same domain should be considered for inclusion in a core outcome set of patient-reported outcome measures to assess the effectiveness and efficacy of perioperative pain management.

The role of evolving concepts and new technologies and approaches in advancing pain research, management, and education since the establishment of the International Association for the Study of Pain

ABSTRACT

The decades since the inauguration of the International Association for the Study of Pain have witnessed major advances in scientific concepts (such as the biopsychosocial model and chronic primary pain as a disease in its own right) and in new technologies and approaches (from molecular biology to brain imaging) that have inspired innovations in pain research. These have guided progress in pain management and education about pain for healthcare professionals, the general public, and administrative agencies.

NIH HEAL Clinical Data Elements (CDE) implementation: NIH HEAL Initiative IMPOWR network IDEA-CC

OBJECTIVE

The National Institutes of Health (NIH) HEAL Initiative is making data findable, accessible, interoperable, and reusable (FAIR) to maximize the value of the unprecedented federal investment in pain and opioid-use disorder research. This involves standardizing the use of common data elements (CDE) for clinical research.

METHODS

This work describes the process of the selection, processing, harmonization, and design constraints of CDE across a pain and opioid use disorder clinical trials network (NIH HEAL IMPOWR).

RESULTS

The network alignment allowed for incorporation of newer data standards across the clinical trials. Specific advances included geographic coding (RUCA), deidentified patient identifiers (GUID), shareable clinical survey libraries (REDCap), and concept mapping to standardized concepts (UMLS).

CONCLUSIONS

While complex, harmonization across a network of chronic pain and opioid use disorder clinical trials with separate interventions can be optimized through use of CDEs and data standardization processes. This standardization process will support the robust secondary data analyses. Scaling this process could standardize CDE results across interventions or disease state which could help inform insurance companies or government organizations about coverage determinations. The development of the HEAL CDE program supports connecting isolated studies and solutions to each other, but the practical aspects may be challenging for some studies to implement. Leveraging tools and technology to simplify process and create ready to use resources may support wider adoption of consistent data standards.

Predicting severe pain after major surgery: a secondary analysis of the Peri-operative Quality Improvement Programme (PQIP) dataset

Acute postoperative pain is common, distressing and associated with increased morbidity. Targeted interventions can prevent its development. We aimed to develop and internally validate a predictive tool to pre-emptively identify patients at risk of severe pain following major surgery. We analysed data from the UK Peri-operative Quality Improvement Programme to develop and validate a logistic regression model to predict severe pain on the first postoperative day using pre-operative variables. Secondary analyses included the use of peri-operative variables. Data from 17,079 patients undergoing major surgery were included. Severe pain was reported by 3140 (18.4%) patients; this was more prevalent in females, patients with cancer or insulin-dependent diabetes, current smokers and in those taking baseline opioids. Our final model included 25 pre-operative predictors with an optimism-corrected c-statistic of 0.66 and good calibration (mean absolute error 0.005, p = 0.35). Decision-curve analysis suggested an optimal cut-off value of 20-30% predicted risk to identify high-risk individuals. Potentially modifiable risk factors included smoking status and patient-reported measures of psychological well-being. Non-modifiable factors included demographic and surgical factors. Discrimination was improved by the addition of intra-operative variables (likelihood ratio χ2 496.5, p < 0.001) but not by the addition of baseline opioid data. On internal validation, our pre-operative prediction model was well calibrated but discrimination was moderate. Performance was improved with the inclusion of peri-operative covariates suggesting pre-operative variables alone are not sufficient to adequately predict postoperative pain.

Prevalence of postoperative pain after hospital discharge: systematic review and meta-analysis

Assessment and management of postoperative pain after hospital discharge is very challenging. We conducted a systematic review to synthesize available evidence on the prevalence of moderate-to-severe postoperative pain within the first 1 to 14 days after hospital discharge. The previously published protocol for this review was registered in PROSPERO. MEDLINE and EMBASE databases were searched until November 2020. We included observational postsurgical pain studies in the posthospital discharge setting. The primary outcome for the review was the proportion of study participants with moderate-to-severe postoperative pain (eg, pain score of 4 or more on a 10-point Numerical Rating Scale) within the first 1 to 14 days after hospital discharge. This review included 27 eligible studies involving a total of 22,108 participants having undergone a wide variety of surgical procedures. The 27 studies included ambulatory surgeries (n = 19), inpatient surgeries (n = 1), both ambulatory and inpatient surgeries (n = 4), or was not specified (n = 3). Meta-analyses of combinable studies provided estimates of pooled prevalence rates of moderate-to-severe postoperative pain ranging from 31% 1 day after discharge to 58% 1 to 2 weeks after discharge. These findings suggest that moderate-to-severe postoperative pain is a common occurrence after hospital discharge and highlight the importance of future efforts to more effectively evaluate, prevent, and treat postsurgical pain in patients discharged from the hospital.

Acute pain management and long term outcomes

PURPOSE OF REVIEW

The acute inflammatory reaction induced by tissue trauma causes pain but also promotes recovery. Recovery is highly variable among peoples. Effective acute pain (AP) management is very important but remains suboptimal what could affect long term outcomes. The review questions the impact of either failure or effectiveness of AP treatments and the choice of analgesic drugs on different long-term outcomes after tissue trauma.

RECENT FINDINGS

Pain control during mobilization is mandatory to reduce the risk of complications which exacerbate and prolong the inflammatory response to trauma, impairing physical recovery. Common analgesic treatments show considerable variability in effectiveness among peoples what argues for an urgent need to develop personalized AP management, that is, finding better responders to common analgesics and targeting challenging patients for more invasive procedures. Optimal multimodal analgesia to spare opioids administration remains a priority as opioids may enhance neuroinflammation, which underlies pain persistence and precipitates neurocognitive decline in frail patients. Finally, recent findings demonstrate that AP treatments which modulate nociceptive and inflammatory pain should be used with caution as drugs which inhibit inflammation like nonsteroidal antiinflammatory drugs and corticoids might interfere with natural recovery processes.

SUMMARY

Effective and safe AP management is of far greater importance than previously realized. Evidence of suboptimal AP management in many patients and recent reports pointing out the impact of current treatments on long term outcomes argue for further research in the field.

Quality indicators for anesthesia and perioperative medicine

PURPOSE OF REVIEW

Routine monitoring of care quality is fundamental considering the high reported rates of preventable perioperative morbidity and mortality. However, no set of valid and feasible quality indicators is available as the gold standard for comprehensive routine monitoring of the overall quality of perioperative care. The purpose of this review is to describe underlying difficulties, to summarize current trends and initiatives and to outline the perspectives in support of suitable perioperative quality indicators.

RECENT FINDINGS

Most perioperative quality indicators used in the clinical setting are based on low or no evidence. Evidence-based perioperative quality indicators validated for research purposes are not always applicable in routine care. Developing a core set of perioperative quality indicators for clinical practice may benefit from matching feasible routine indicators with evidence-based indicators validated for research, from evaluating additional new indicators, and from including patients' views.

SUMMARY

A core set of valid and feasible quality indicators is essential for monitoring perioperative care quality. The development of such a set may benefit from matching evidence-based indicators with feasible standard indicators and from including patients' views.

Effect modifiers of virtual reality in pain management: a systematic review and meta-regression analysis

ABSTRACT

There is a rapidly growing body of evidence for the application of virtual reality (VR) in pain management, however, with varying effectiveness. Little is known about patient-related and VR-related factors affecting efficacy of VR. A systematic review and meta-analysis was performed including 122 randomised controlled trials (9138 patients), reporting on subjectively reported pain scores comparing an immersive VR intervention to a non-VR control group. Virtual reality significantly reduced pain in the pooled analysis (standardized mean difference = -0.65, 95% CI -0.76 to -0.54, P < 0.001). Subgroup analyses showed no significant differences between type of pain, ie, VR effects were similar in acute, chronic, and procedural pain conditions. Univariate and multivariate meta-regression analyses were performed to investigate the effect of intervention, patient, and pain characteristics on VR. Virtual reality effectively reduced pain, especially in patients reporting moderate to severe pain and in younger subjects. Studies comparing VR with a control group receiving no distraction methods were associated with higher effect sizes. The effect of VR was not related to a specific frequency or duration of use. Type of software and interaction level were related to VR effects in the univariable, but not in the multivariable, meta-regression analysis. Heterogeneity was considerable for all meta-analyses, and risk of bias was moderate to high in most included studies. Studies on mechanisms behind VR analgesia in younger patients and patients reporting moderate to severe pain are recommended to confirm our hypotheses while taking into account risk of bias and the comparator. Optimal application of VR using treatment modules for long-term pain conditions are an important issue for future research.

Characteristics, completion and publication of PROSPERO records in regional anesthesia for acute perioperative pain

Aim: We analyzed characteristics and completion status of Systematic Reviews (SRs) about regional anesthesia for acute perioperative pain relief registered in PROSPERO. Materials & methods: PROSPERO was searched on 5 January 2022. Characteristics of PROSPERO records, completion status and publication information were extracted. PubMed and Google Scholar were searched by 31 May 2022, for additional published SRs. The inconsistency of PROSPERO records' status was analyzed by comparing the most recent PROSPERO status with subsequent publication of completed SR. Time-to-publication was calculated. Results: Almost half of 174 included PROSPERO records (49%) were registered in 2021. A median of 3 (IQR: 2-4.75) authors, and a search of 4 information sources (IQR: 3-5) was planned. At first registration, 51 (29%) records had already started or completed formal screening. PROSPERO records included mostly adults (48%) undergoing trunk blocks (56%), with pain intensity (74%) as a main outcome. 147 (84%) PROSPERO records had a status "ongoing". Yet, 71 (41%) PROSPERO records were completed SRs, published after a median of 291 days. Inconsistency in status was found in 34% of PROSPERO records. Conclusion: Despite an increase in PROSPERO registrations about regional anesthesia, most were not published, and a third had inaccurate status.

Scoping review of early pain-related outcome domains and measurement instruments after degenerative lumbar spine surgery

BACKGROUND

Optimization of perioperative pain interventions in lumbar spine surgery could reduce the incidence of acute and persistent postoperative pain and opioid consumption. Standardization in early outcome measurement provides a solid foundation for future clinical and research practices and should be integrated in core outcome sets for long-term treatment outcome evaluations. This scoping review provides an overview of outcomes used when evaluating early perioperative pain interventions after lumbar spine surgery.

OBJECTIVES

To create an overview of outcome domains and measurement instruments previously used in research on perioperative pain management for degenerative lumbar spine surgery.

EVIDENCE REVIEW

A scoping review was performed to identify articles comprising outcome evaluations in adult patients who undergo degenerative lumbar spine surgery, mentioning perioperative pain interventions. 75 articles were included for review. Data on study characteristics, outcome domains and measurement instruments were extracted and structured using the three-tiered hierarchy of Porter.

FINDINGS

12 outcome domains were identified: pain intensity (93.3%), adverse events (76%), analgesic consumption (70.7%), length of stay (52%), patient satisfaction (24%), daily functioning (22.7%), (early) mobilization (22.7%), quality of life (12%), mortality (9.3%), quality of recovery (6.7%), physical function (4%), and quality of sleep (2.7%). 63 corresponding measurement instruments were found.

CONCLUSIONS

This review portrays an extensive overview of outcome measurements used in perioperative pain management in lumbar spine surgery. A lack of consensus on the set of indicators exists. This scoping review is a call for action to create consensus on how to evaluate perioperative pain interventions in degenerative lumbar spine surgery.

Opioid consumption and non-opioid multimodal analgesic treatment in pain management trials after hip and knee arthroplasties: A meta-epidemiological study

BACKGROUND

The leading principle in peri-operative pain management is multimodal analgesia, which reduces opioid requirements and associated adverse effects. Pragmatic pain trials should optimally test interventions in addition to multimodal non-opioid analgesics and interventions to ensure clinical relevance and baseline levels of opioid consumption that reflect clinical settings. We aimed to investigate opioid consumption and use of non-opioid analgesics administered adjunct to interventions in post-operative pain trials after total hip and knee arthroplasty.

METHODS

A systematic literature search was conducted 7 January 2020 in The Cochrane Library's CENTRAL, PubMed, and EMBASE. Trials investigating analgesic interventions for post-operative pain in adults undergoing total hip or knee arthroplasty were included. The primary outcome was the aggregated median 0-24 h post-operative opioid consumption. Further, we assessed the use of paracetamol, non-steroidal anti-inflammatory drugs, gabapentinoids, high-dose glucocorticoids, local infiltration analgesia and nerve blocks administered as co-interventions equally to all participants. We assessed trends over time for all outcomes.

RESULTS

Of 14,200 records, 570 trials were included. Median 0-24 h opioid consumption was 21 and 22 mg iv morphine equivalents in hip and knee arthroplasty trials, respectively. Meta-regression showed no overall linear correlation between opioid consumption and publication year. The use of multimodal non-opioid analgesia increased over time, though only 48% of trials published from 2010 to 2020 administered two or more non-opioid analgesics. Applying more non-opioid analgesics was associated with lower opioid consumption in intervention groups.

CONCLUSION

Post-operative 0-24 h morphine consumption was median 21-22 mg. The demonstrated differences in non-opioid multimodal analgesic regimens between research and clinical settings, can potentially diminish the demonstrated opioid-sparing effects of trial interventions when such are implemented in a clinical context.

Fairness in the prediction of acute postoperative pain using machine learning models

Introduction

Overall performance of machine learning-based prediction models is promising; however, their generalizability and fairness must be vigorously investigated to ensure they perform sufficiently well for all patients.

Objective

This study aimed to evaluate prediction bias in machine learning models used for predicting acute postoperative pain.

Method

We conducted a retrospective review of electronic health records for patients undergoing orthopedic surgery from June 1, 2011, to June 30, 2019, at the University of Florida Health system/Shands Hospital. CatBoost machine learning models were trained for predicting the binary outcome of low (≤4) and high pain (>4). Model biases were assessed against seven protected attributes of age, sex, race, area deprivation index (ADI), speaking language, health literacy, and insurance type. Reweighing of protected attributes was investigated for reducing model bias compared with base models. Fairness metrics of equal opportunity, predictive parity, predictive equality, statistical parity, and overall accuracy equality were examined.

Results

The final dataset included 14,263 patients [age: 60.72 (16.03) years, 53.87% female, 39.13% low acute postoperative pain]. The machine learning model (area under the curve, 0.71) was biased in terms of age, race, ADI, and insurance type, but not in terms of sex, language, and health literacy. Despite promising overall performance in predicting acute postoperative pain, machine learning-based prediction models may be biased with respect to protected attributes.

Conclusion

These findings show the need to evaluate fairness in machine learning models involved in perioperative pain before they are implemented as clinical decision support tools.

Pain, pain management and related outcomes following pelvic exenteration surgery: a systematic review

AIM

Pelvic exenteration surgery can improve survival in people with advanced colorectal cancer. This systematic review aimed to review pain intensity and other outcomes, for example the management of pain, the relationship between pain and the extent of surgery and the impact of pain on short-term outcomes.

METHOD

Electronic databases were searched from inception to 1 May 2021. We included interventional studies of adults with any indication for pelvic exenteration surgery that also reported pain outcomes. Risk of bias was assessed using ROBINS-1.

RESULTS

The search found 21 studies that reported pain following pelvic exenteration [n = 1317 patients, mean age 58.4 years (SD 4.8)]. Ten studies were judged to be at moderate risk of bias. Before pelvic exenteration, pain was reported by 19%-100% of patients. Five studies used validated measures of pain intensity. No study measured pain at all three time points in the surgical journey. The presence of pain before surgery predicted postoperative adverse pain outcomes, and pain is more likely to be experienced in those who require wider resections, including bone resection.

CONCLUSION

Considering that pain following pelvic exenteration is commonly described by patients, the literature suggests that this symptom is not being measured and therefore addressed.

Implementation of a peri-operative pain-management algorithm reduces the use of opioid analgesia following pelvic exenteration surgery

AIM

This study aimed to investigate the implementation and pain-related outcomes of a peri-operative pain-management regimen for patients undergoing pelvic exenteration surgery at a university teaching hospital.

METHOD

This is a single-site prospective observational cohort study involving 100 patients who underwent pelvic exenteration surgery between January 2017 and December 2018. A pain-management algorithm regarding the use of opioid-sparing multimodal analgesia was developed between the departments of anaesthesia, pain management and intensive care. The primary outcomes were: compliance with a pain-treatment algorithm compared with a similar retrospective surgical patient cohort in 2013-2014; and requirements for regular doses of opioid analgesia at discharge, measured in oral morphine equivalent daily dose (oMEDD).

RESULTS

Following the introduction of a pain-management algorithm, regional anaesthesia techniques (spinal anaesthesia, transversus abdominus plane block, preperitoneal catheters or epidural analgesia) were used in 83/98 (84.7%) of the 2017-2018 cohort compared with 13/73 (17.8%) of the 2013-2014 cohort (p < 0.001). There was a reduction in the median dose of opioid analgesics (oMEDD) at time of discharge, from 150 mg (interquartile range [IQR]: 75.0-235.0 mg) in the 2013-2014 cohort to 10 mg (IQR: 0.00-45.0 mg) in the 2017-2018 cohort (p < 0.001). There was no change in pain intensity (assessed using the Verbal Numerical Rating Score) or oMEDD in the first 7 days following surgery.

CONCLUSION

Since implementation of a novel peri-operative pain-treatment algorithm, the use of opioid-sparing regional techniques and preperitoneal catheters has increased. Additionally, the dose of opioids required at the time of discharge has reduced significantly.

Pathophysiology, diagnosis, and management of endometriosis

Endometriosis affects approximately 190 million women and people assigned female at birth worldwide. It is a chronic, inflammatory, gynecologic disease marked by the presence of endometrial-like tissue outside the uterus, which in many patients is associated with debilitating painful symptoms. Patients with endometriosis are also at greater risk of infertility, emergence of fatigue, multisite pain, and other comorbidities. Thus, endometriosis is best understood as a condition with variable presentation and effects at multiple life stages. A long diagnostic delay after symptom onset is common, and persistence and recurrence of symptoms despite treatment is common. This review discusses the potential genetic, hormonal, and immunologic factors that lead to endometriosis, with a focus on current diagnostic and management strategies for gynecologists, general practitioners, and clinicians specializing in conditions for which patients with endometriosis are at higher risk. It examines evidence supporting the different surgical, pharmacologic, and non-pharmacologic approaches to treating patients with endometriosis and presents an easy to adopt step-by-step management strategy. As endometriosis is a multisystem disease, patients with the condition should ideally be offered a personalized, multimodal, interdisciplinary treatment approach. A priority for future discovery is determining clinically informative sub-classifications of endometriosis that predict prognosis and enhance treatment prioritization.

Efficacy and safety of co-crystal of tramadol-celecoxib (CTC) in acute moderate-to-severe pain after abdominal hysterectomy: A randomized, double-blind, phase 3 trial (STARDOM2)

BACKGROUND

STARDOM2 is a randomized, double-blind, phase 3 trial evaluating the efficacy and safety of co-crystal of tramadol-celecoxib (CTC)-a first-in-class analgesic co-crystal comprising racemic tramadol hydrochloride and celecoxib in a supramolecular network that modifies their pharmacokinetic properties-for the management of acute postoperative pain (NCT03062644; EudraCT:2016-000593-38).

METHODS

Patients with moderate-to-severe pain following abdominal hysterectomy were randomized 2:2:2:2:2:1 to oral CTC 100 mg (rac-tramadol hydrochloride 44 mg/celecoxib 56 mg) twice daily (BID); CTC 150 mg (66/84 mg) BID; CTC 200 mg (88/112 mg) BID; immediate-release tramadol 100 mg four times daily (QID); celecoxib 100 mg BID; or placebo, for 5 days. The primary endpoint was the sum of pain intensity differences over 0-4 h (SPID_0-4 ). Key secondary endpoints were rescue medication use within 4 h, 50% response rate at 4 h, and safety/tolerability.

RESULTS

Of 1355 patients enrolled, 1138 were randomized (full analysis set) and 1136 treated (safety analysis set). In the prespecified gatekeeping analysis of SPID_0-4 , CTC 200 mg was not superior to tramadol but showed non-inferior efficacy (p < 0.001) that was sustained throughout the 120-h period, despite a 5-day cumulative tramadol administration of 880 mg with CTC 200 mg BID versus 2000 mg with tramadol 100 mg QID. Treatment-emergent adverse events (TEAEs) and severe TEAEs were less common with CTC 200 mg versus tramadol. Treatment-related TEAEs were 14.4% with CTC 200 mg and 23.6% with tramadol.

CONCLUSIONS

Although the study did not meet its primary endpoint, CTC 200 mg showed a clinically relevant improvement in overall benefit/risk profile versus tramadol alone, with considerably lower cumulative opioid exposure.

SIGNIFICANCE

In the randomized, double-blind, phase 3 STARDOM2 trial-in acute moderate-to-severe pain after abdominal hysterectomy-the novel co-crystal of tramadol-celecoxib (CTC) 200 mg BID was superior to placebo and non-inferior to tramadol 100 mg QID. Although superiority to tramadol was not reached, CTC 200 mg BID exposed patients to lower cumulative opioid (tramadol) doses than tramadol (100 mg QID) alone, with fewer treatment-emergent adverse events. CTC 200 mg thus has a clinically relevant improved benefit/risk profile compared with tramadol alone.

[Perioperative Pain Management in Children]

Acute pain therapy in children is highly complex. Already preoperatively, the course for a successful therapy is set in the interaction with the child and parents. The goal of the treatment is a satisfied child. This means the use of empathy and therapy planning aimed at a balance between effect and side effect and functionality. Modern concepts are opioid-sparing and procedure-specific. Regional anaesthesia plays a major role, among other things due to excellent safety data. Knowledge of age- and block-specific local anaesthetic dosages is essential. Little is known about pharmacodynamic data of analgesics in children. Although knowledge about pharmacokinetic characteristics is increasing, off-label use of analgesics is inevitable. International databases such as the Kinderformularium provide up-to-date information. When using opioids, rules for safe handling must be followed both in terms of use and prescribing. Non-opioids and adjuvants - individually or in combination - have an established place in perioperative pain management. Non-pharmacological interventions can reduce anxiety and pain. Anxiety is one of the risk factors for chronic postsurgical pain.

Investigating the Role of Ly6G+ Neutrophils in Incisional and Inflammatory Pain by Multidimensional Pain-Related Behavioral Assessments: Bridging the Translational Gap

In recent years, preclinical pain research has failed to develop genuinely new analgesics for clinical use. This fact is reflected by a high number of patients, limited drug efficacy accompanied by side effects, and a long-term opioid intake. Two main aspects have been addressed, which hinder translation: the use of non-relevant pain models and a mismatch between pain-related outcomes in preclinical and clinical studies. Conversely, disease-specific pain models that mirror more closely the clinical situation and multidimensional behavioral outcome measures that objectively and reproducibly assess relevant pain-related symptoms in a preclinical setting could improve translation. Mechanistically, a matter of debate is the role of Ly6G⁺ neutrophil granulocytes (NGs) for pain. NGs are essential to eliminate pathogens and promote the wound healing process. For this purpose, there is a need to release various pro- and anti-inflammatory mediators, some of which could ameliorate or enhance pain. However, the contribution of NGs to different pain entities is contradictory for reflex-based tests, and completely unknown in the context of non-evoked pain (NEP) and movement-evoked pain (MEP). First, we combined withdrawal reflex-based assays with novel video-based assessments for NEP- and MEP-related behavior in two mouse pain models. The pain models utilized in this study were incision (INC) and pathogen/adjuvant-induced inflammation (CFA), translating well to postsurgical and inflammatory pain entities. Second, we depleted NGs and applied a set of behavioral assessments to investigate the role of NG migration in different pain modalities. Our comprehensive behavioral approach identified pain-related behaviors in mice that resemble (NEP) or differentiate (MEP) behavioral trajectories in comparison to mechanical and heat hypersensitivity, thereby indicating modality-dependent mechanisms. Further, we show that injury-induced accumulation of NGs minimally affects pain-related behaviors in both pain models. In conclusion, we report a novel assessment to detect NEP in mice after unilateral injuries using a more unbiased approach. Additionally, we are capable of detecting an antalgic gait for both pain entities with unique trajectories. The different trajectories between MEP and other pain modalities suggest that the underlying mechanisms differ. We further conclude that NGs play a subordinate role in pain-related behaviors in incisional and inflammatory pain.